Only in the field of library science can random websurfing be considered professional development! As I eagerly run out the clock here on my last Sunday afternoon at the Circ Desk until late September, I've happened to stumble upon a couple of useful links for the aspiring reference librarian:
NationMaster - "(A) massive central data source and a handy way to graphically compare nations. NationMaster is a vast compilation of data from such sources as the CIA World Factbook, United Nations, World Health Organization, World Bank, World Resources Institute, UNESCO, UNICEF and OECD. Using the form above, you can generate maps and graphs on all kinds of statistics with ease."
Wikipedia - An open-source encyclopedia available free online in multiple languages. You may already know about this resource, which grows more and more useful with every new contribution, but it bears repeating nonetheless. My favorite feature: a link that takes you to a randomly-selected Wikipedia page.
At some point I'm going to put a set of Ready Reference links on the sidebar, if for no one else's benefit but my own!